Many electronic devices, such as calculators, are designed to accept one or more plug-in integrated circuit modules to enhance the flexibility or the capacity of the device. One example is a calculator, disclosed in U.S. Pat. No. 4,063,221 of Watson, Walden, and Near, which accepts plug-in read-only memory modules. These modules allow the user to tailor the configuration of the calculator to meet the user's specific needs, by providing a range of mathematical and statistical capabilities appropriate to a given task.
Such modules, while functional, may not be entirely satisfactory in use because of susceptibility to damage from electrostatic discharges experienced in handling. Damage to an integrated circuit can result when an electrostatic discharge produces a differential voltage across the circuit "pins" or contact leads. High voltages can cause physical disruption within the circuit, while low voltages may alter the contents of stored memory.